Plasma procalcitonin concentrations predict organ dysfunction and outcome in dogs with sepsis

Serum procalcitonin as a diagnostic biomarker in dogs with bacterial respiratory diseases

BACKGROUND

Procalcitonin (PCT) is a useful biomarker in humans in the identification of bacterial respiratory infections.

OBJECTIVES

The aim of this study was to investigate the utility of serum PCT measurements as a diagnostic biomarker in canine bacterial lower respiratory tract diseases.

METHODS

PCT concentrations were measured in serum samples with an ELISA method previously validated for dogs. All dogs underwent thorough clinical examinations, and the diagnosis of respiratory disease was based on clinical and laboratory findings, diagnostic imaging, as well as cytology and bacterial culture of respiratory samples. PCT concentrations between different cohorts of dogs were compared with an ANOVA-model.

RESULTS

Sixty-two privately owned dogs with respiratory diseases, 25 with bacterial pneumonia (BP), 17 with bacterial bronchitis caused by Bordetella bronchiseptica (BB), and 20 with chronic bronchitis (CB) as well as 44 healthy controls were included in the study. Serum PCT concentrations in dogs with bacterial respiratory diseases (BP mean 51.8 ng/L ± standard deviation [SD] 40.6 ng/L and BB mean 61.4 ng/L ± SD 35.3 ng/L) were not significantly different when compared with dogs with a non-bacterial respiratory disease (CB mean 89.7 ± SD 73.5 ng/L) or healthy dogs (mean 51.0 ng/L ± SD 37.5 ng/L, p > .05 in all comparisons).

CONCLUSIONS

These results indicate that despite being a valuable diagnostic, prognostic, and follow-up marker in humans with pneumonia, serum PCT concentrations are not elevated in dogs with bacterial respiratory diseases and, therefore, cannot be used as a diagnostic biomarker in dogs.

New-onset organ dysfunction as a screening tool for the identification of sepsis and outcome prediction in dogs with systemic inflammation

Introduction

Sepsis in people is defined as a life-threatening organ dysfunction (OD) caused by a dysregulated host response to infection. In veterinary medicine, sepsis is still defined by the presence of systemic inflammation plus the evidence of infection. Based on recent veterinary studies, multiorgan dysfunction syndrome (MODS) has been associated with a worse outcome in sepsis. Thus, the screening for OD is warranted to identify the most critically ill patients. The aim of this study was to investigate the diagnostic value of new-onset OD for the prediction of sepsis and outcome in a population of critically ill dogs with systemic inflammation.

Materials and methods

Dogs admitted to the Emergency Room and/or the Intensive Care Unit with systemic inflammation, defined by a serum C-reactive protein concentration > 1.6 mg/dL, were retrospectively included. Enrolled dogs were categorized according to the presence of sepsis or non-infectious systemic inflammation. The presence of newly diagnosed OD was assessed based on criteria adapted from human literature and previously reported canine criteria.

Results

275 dogs were included: 128 had sepsis and 147 had non-infectious systemic inflammation. The frequency of new-onset OD was not different between these groups. Only the presence of fluid-refractory hypotension was significantly associated with a diagnosis of sepsis (OR 10.51, 3.08-35.94; p < 0.0001). The frequency of at least two ODs was significantly higher in non-survivors compared to survivors, according to both the human and the veterinary criteria considered for the study (p = 0.0001 and p = 0.0004, respectively). Specifically, the presence of acute kidney injury, stupor or coma, prolonged Prothrombin Time and decreased Base Excess were associated with a higher risk of death in the multivariate binary logistic regression.

Discussion

In this population of critically ill dogs with systemic inflammation, the detection of newly diagnosed ODs was not able to predict sepsis diagnosis, other than the presence of fluid-refractory hypotension. However, given the strong prognostic significance associated with ODs, our results support the early screening for ODs in any severe inflammatory critical care condition to identify high-risk patients and optimize their management.

Plasma procalcitonin kinetics in healthy dogs and dogs undergoing tibial plateau leveling osteotomy

BACKGROUND

Procalcitonin (PCT) is a well-established biomarker for bacterial infection in human patients.

OBJECTIVES

We aimed to analyze the kinetics of plasma PCT (pPCT) in healthy dogs and dogs with canine cranial cruciate ligament (CCL) rupture undergoing tibial plateau leveling osteotomy (TPLO).

METHODS

This prospective, longitudinal study included 15 healthy dogs and 25 dogs undergoing TPLO. Hematology, pPCT, and C-reactive protein (CRP) were assessed on 3 consecutive days in healthy dogs and 1 day preoperatively and days 1, 2, 10, and 56 postoperatively. Inter- and intraindividual variability of pPCT were assessed in healthy dogs. Median pPCT concentrations of dogs with CCL rupture preoperatively were compared with healthy controls, and median pPCT concentrations, as well as percentage change post anesthesia, arthroscopy, and TPLO, were compared with baseline. For the correlation analysis, the Spearman rank correlation test was used.

RESULTS

Inter- and intraindividual variabilities of pPCT in healthy dogs were 36% and 15%, respectively. Median baseline pPCT concentrations were not significantly different between healthy dogs (118.9 pg/mL; IQR: 75.3-157.3 pg/mL) and dogs undergoing TPLO (95.9 pg/mL; IQR: 63.8-117.0 pg/mL). Plasma PCT concentrations were significantly lower immediately post- than preoperatively (P < 0.001). CRP, WBC, and neutrophil concentrations increased significantly on post-OP day 2 and had normalized by day 10.

CONCLUSIONS

These results indicate that CCL rupture, as well as anesthesia, arthroscopy, and TPLO combined, are not associated with increased pPCT concentrations in dogs with uncomplicated recovery. Considering the high intraindividual variability, individual serial measurements rather than a population-based reference interval should be considered.

Evaluation of the neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in critically ill dogs

OBJECTIVE

To evaluate whether the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are accurate prognostic indicators and correlate with illness severity scores in critically ill dogs.

DESIGN

Prospective observational study from December 2016 to May 2017.

SETTING

ICU at a veterinary teaching hospital.

ANIMALS

Seventy-two client-owned dogs admitted to the ICU with CBCs and abbreviated and complete acute patient physiologic and laboratory evaluation (APPLE_fast and APPLE_full ) scores were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The NLR, PLR, APPLE_fast , and APPLE_full scores were calculated for each patient on the day of admission. Patients were followed from admission to discharge, and diagnosis, survival, and length of hospitalization were recorded. The patient population was assessed as a whole and as subcategories of patients with neoplastic disease, infectious disease, sepsis, and severe hemorrhage. Dogs with nonseptic disease processes (n = 52) that died had a significantly higher median PLR (P = 0.04) of 441 (range: 106-986) compared to those that survived with a median PLR of 217 (range: 28.4-3225). The PLR was strongly predictive of ICU length of stay in dogs with severe hemorrhage (P = 0.03, Spearman's rho = 0.84). The NLR had a poor positive correlation with APPLE_full score (P = 0.04, Spearman's rho = 0.24), and PLR had a poor negative correlation with APPLE_fast score (P = 0.02, Spearman's rho = -0.27).

CONCLUSIONS

The PLR correlated with ICU length of stay for patients with severe hemorrhage and with survival for patients with nonseptic disease processes. The PLR and NLR correlated with illness severity as measured by APPLE scores. Future studies with larger sample sizes are warranted to further determine the merit of NLR and PLR as indicators of morbidity, mortality, and illness severity.

Apolipoprotein A1 and serum amyloid A in dogs with sepsis and septic shock

Introduction

Apolipoprotein-A1 (Apo-A1) acts as a negative acute phase protein (APP) during inflammatory states, and has a potential prognostic value in people and dogs with sepsis. The aim of this retrospective study was to investigate the association of serum Apo-A1 concentration with disease severity, multiorgan dysfunction syndrome (MODS) and outcome in a population of dogs with sepsis, and to assess its correlation with major canine APPs.

Methods

Ninety-nine dogs with uncomplicated sepsis (n = 78) or septic shock (n = 21) were included. The serum concentration of Apo-A1, C-reactive protein (CRP) and serum amyloid A (SAA) were recorded, alongside the canine acute patient physiologic and laboratory evaluation fast (APPLE_fast) score and the presence of MODS.

Results

Dogs with septic shock had significantly lower serum Apo-A1 concentrations (106.3 ± 22.7 mg/dl; reference interval: 123.0-142.3 mg/dl), higher APPLE_fast score (30, 13-38) and greater frequency of MODS (67%) compared to those with uncomplicated sepsis (117.9 ± 19.3 mg/dl; 25, 6-33 and 8%, respectively) (P = 0.0201; P = 0.0005; P < 0.0001, respectively). Similarly, dogs with MODS had significantly lower serum Apo-A1 concentrations (104.1 ± 4.6 mg/dl) and higher APPLE_fast score values (31, 13-38) compared to those without MODS (118.32 ± 2.1 mg/dl and 26, 6-33, respectively) (P = 0.0050 and P = 0.0038, respectively). Conversely, neither CRP nor SAA were different between these groups. No difference in serum APPs concentrations was detected between survivors and non-survivors. Significant negative correlations were detected between serum Apo-A1 and SAA (P = 0.0056, r = -0.277), and between serum Apo-A1 and the APPLE_fast score (P = 0.0027, r = -0.3). In this population, higher values of the APPLE_fast score and the presence of MODS were independently associated with a higher risk of death.

Discussion

Our study shows that Apo-A1 is a useful biomarker of sepsis severity in dogs, since it is decreased in those with septic shock and MODS. Further prospective investigations are deemed to evaluate the applicability of Apo-A1 to predict sepsis course and response to treatment in septic dogs.

Molecularly imprinted polymers as effective capturing receptors in a pseudo-ELISA immunoassay for procalcitonin detection in veterinary species

In this study, a new sandwich-type immunoenzymatic assay, based on a molecularly imprinted polymer (MIP) as an artificial antibody (pseudo-ELISA), was developed for the determination of procalcitonin (PCT) in veterinary species. The quantification of PCT in human medicine represents the state of the art for the diagnosis of sepsis; instead the clinical studies on the relevance of PCT as a sepsis predictor in veterinary patients are few, likely due to the total absence of validated assays. MIPs have been widely used as antibody mimics for important applications, and MIP-based sandwich assays have emerged as promising analytical tools for the detection of disease biomarkers. Herein, a polynorepinephrine (PNE)-based imprinted film was directly synthesized on the well surface of a 96-well plate. Subsequently, based on a commercial ELISA kit, the PCT quantification was accomplished via a colorimetric sandwich assay by replacing the capture antibody of the kit with the PNE-based MIP. This method was performed to detect canine and equine PCT in buffer and in plasma samples. Under optimal conditions, the results obtained in plasma samples showed a limit of detection (LOD) of 5.87 ng mL^-1 and a reproducibility (CV_av%) of 10.0% for canine samples, while a LOD = 4.46 ng mL^-1 and CV_av% = 7.61% were obtained for equine samples.

Use of serum procalcitonin (PCT) level and PCT mRNA expression as a potential clinical biomarker in cats with bacterial and viral infections

OBJECTIVES

The aim of this study was to investigate the use of procalcitonin (PCT) as a biomarker in differentiating bacterial infections from viral infections in cats. In addition, the relationship between PCT and mortality rate was also examined.

METHODS

Forty-five cats were included in the study. The cats were categorised into two groups: bacterial (n = 20) and viral (n = 25) infection. Serum PCT level and PCT mRNA expression were analysed from blood samples collected before treatment.

RESULTS

Serum PCT level and PCT mRNA expression of the cats with presumed bacterial infection were higher than those with viral infection (P = 0.001 and P = 0.001, respectively). The receiver operating characteristic (ROC) curve analysis revealed an area under the ROC curve value of 0.888 for serum PCT and 0.850 for PCT mRNA expression. There was no statistically significant difference among respiratory, urinary and gastrointestinal tract infections regarding serum PCT level and PCT mRNA expression in the presumed bacterial infection group (P = 0.741 and P = 0.141, respectively). In the presumed bacterial infection group, serum PCT level and PCT mRNA expression in the non-surviving cats were higher than those of the surviving cats (P = 0.021 and P = 0.026, respectively).

CONCLUSIONS AND RELEVANCE

Serum PCT level and PCT mRNA expression were considered efficient biomarkers in cats to distinguish a bacterial infection from a viral infection. Moreover, ROC curve analysis was highly accurate in the discriminative capacity of these two parameters. PCT level and PCT mRNA expression offer substantial assistance in an efficient therapeutic approach and in avoiding unnecessary antibiotic use in feline clinical practice, particularly in emergency patients and those with non-specific clinical signs, decreasing the mortality rate. However, it should be noted that these data are only research data. More detailed future studies are needed.

Serial analysis of blood biomarker concentrations in dogs with pneumonia, septic peritonitis, and pyometra

BACKGROUND

Prolonged antimicrobial drug (AMD) treatment is associated with antimicrobial resistance development. Biomarker measurement may aid treatment decision-making.

OBJECTIVES

Investigate temporal changes in blood biomarker concentrations in dogs undergoing treatment for pulmonary and intra-abdominal infections; compare time to biomarker concentration normalization with duration of clinician-directed AMD treatment.

ANIMALS

Forty-two client-owned dogs with pneumonia (n = 22), septic peritonitis (n = 10), or pyometra (n = 10).

METHODS

Plasma concentrations of C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin, procalcitonin, nucleosomes, cell-free DNA (cfDNA), high-mobility group box-1 (HMGB1), CC-motif chemokine ligand-2 (CCL2), CXC-motif chemokine ligand-8 (CXCL8), and keratinocyte chemoattractant-like (KC-Like) were quantitated in samples collected on days 1, 3, 7, 14, 28, and 60. Treatment was directed by clinicians blinded to biomarker concentrations.

RESULTS

Concentrations of CCL2, CRP, and KC-Like were maximal on D1, concentrations of SAA, cfDNA, HMGB1, and nucleosomes were maximal on D3 and haptoglobin concentrations were maximal on D7. These maximal concentrations were significantly different from those on D60. Concentrations of CRP and SAA decreased by 80% from peak and into respective reference intervals before AMDs were discontinued. For CRP, the median (interquartile range [IQR]) times to 20% peak and normal were 7 (6-9) and 7 (6-12) days, respectively, and for SAA they were 4 (4, 5) and 6 (5-8) days, respectively, compared to a median (IQR) duration of AMD prescribing of 16 (12-23) days (all P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Biomarker concentrations normalized within 7 to 14 days. Serial measurements of CRP and SAA might aid identification of disease resolution and could help guide AMD prescription decision-making.

Can Procalcitonin Be Dosed in Bovine Milk Using a Commercial ELISA Kit?

Simple Summary

Mastitis is one of the major economic and animal welfare problems on dairy farms. The gold standard test for mastitis diagnosis is milk culture, but bacteria are not always isolated (only in 11–44% of milk samples from clinical cases of mastitis) and sometimes a positive culture can result from a contamination of the milk. Procalcitonin is a new biomarker which may lead to an early detection of inflammation due to bacterial infection. In humans, procalcitonin concentration has also been evaluated in milk in addition to plasma. The authors aimed to evaluate the possible application of a commercially available ELISA kit for bovine procalcitonin for the assessing of procalcitonin in bovine milk samples. Plasma and milk samples from cows with mastitis were collected to measure procalcitonin concentrations by using a bovine procalcitonin ELISA kit. Our results showed that the ELISA kit tested can be employed to assess bovine procalcitonin in plasma but not for analyzing milk samples.

Abstract

The aim was to evaluate the use of a bovine procalcitonin (PCT) ELISA kit (Cusabio, China) for assessing PCT in bovine milk samples. Validation was performed by using 10 plasma and corresponding milk samples from mastitic cows. The limit of detection (LOD) was calculated. The coefficient of variation (CV%) of the readings of five plasma samples measured five times in the same plate (intra-assay) and the CV% of the same five samples read five times in three separate plates was evaluated. Parallelism was determined by serial twofold dilutions of five plasma and corresponding milk samples. Milk samples were analyzed with and without centrifugation. Regarding plasma PCT, the method presented an inter- and intra-CV < 23.7% and parallelism had very good recovery values. The ELISA kit studied can measure bovine plasma PCT concentrations. The kit antibodies fail in binding PCT in milk samples because all centrifuged milk samples showed a lower LOD than blank samples. Only three uncentrifuged milk samples showed measurable PCT concentrations. Due to these results, the commercial ELISA kit investigated could not be employed for the detection of PCT in milk samples.

Investigation of procalcitonin and beta-defensin2 in the serum and feces of dogs with acute diarrhea

BACKGROUND

Acute diarrhea is a common clinical condition where clinical parameters are used to assess disease severity, course, and prognosis.

OBJECTIVES

The aim of this study was to investigate procalcitonin (PCT) and beta-defensin2 (Bdef2) as biomarkers for disease severity, course, and prognosis of dogs with acute diarrhea.

METHODS

Dogs with acute diarrhea (enteritis group [EG], n = 35) were compared with 30 healthy controls. The dogs in the EG were scored using the Canine Acute Diarrhea Severity (CADS) index and grouped by bacterial fecal culture results. Procalcitonin and Bdef2 were analyzed in serum and feces.

RESULTS

Dogs with acute diarrhea showed higher serum PCT concentrations (P < 0.0001) and lower fecal Bdef2 concentrations (P = 0.0001) than unaffected dogs. Serum PCT was moderately and positively related to the extent of disease classified by the CADS score. Dogs with Clostridium perfringens or hemolyzing Escherichia coli as predominant pathogen had increased serum Bdef2 concentrations (P < 0.01). Differentiation between uncomplicated (≤3 days) and complicated (>3 days) disease courses, determined by receiver operating characteristic (ROC) curves, resulted in a sensitivity of 0.74 and a specificity of 0.69 for serum PCT at a cutoff of 3.9 ng/mL. The serum PCT and fecal Bdef2 quotient resulted in a sensitivity of 0.80 and a specificity of 0.92, with a cutoff of 80.5.

CONCLUSIONS

The results of the present study indicate that PCT and Bdef2 are potential biomarkers that can provide information on the severity, course, and prognosis of acute diarrhea in dogs.

Neutrophil to lymphocyte ratio as a prognostic biomarker in puppies with acute diarrhea

OBJECTIVES

To document the neutrophil to lymphocyte ratio (NLR) values in systemic inflammatory response syndrome positive (SIRS+) and negative (SIRS-) puppies presenting with acute diarrhea (AD). To determine whether the calculated canine acute diarrhea severity index (CADSI) score was associated with NLR. Also, to investigate the prognostic value of NLR in puppies with acute diarrhea.

DESIGN

Retrospective study.

SETTING

University veterinary teaching hospital.

ANIMALS

A total of 85 puppies (2-6 months old), 70 with AD and 15 healthy controls (CON).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pertinent history, physical examination findings and results of complete blood count analysis of dogs with AD at the time of admission to the hospital were obtained from medical records. Forty-seven of the dogs with AD were SIRS+ and 23 were SIRS-. Of the puppies with AD, 11 died within 7 days after initiation of treatment, 59 survived. NLR values in dogs with AD were statistically higher (P < 0.001) than the CON group, but there was no difference (P = 0.791) between the two groups in terms of white blood cell (WBC) count. The median NLR of SIRS+ (3.66) dogs was significantly higher than the median NLRs of dogs in the SIRS- (1.88) and CON (1.35) groups. While a strong positive correlation (ρ = 0.740; P < 0.001) was found between the CADSI score and NLR in dogs with AD, the relationship between WBC and disease severity was not significant (ρ = -0.117; P = 0.336). The area under the receiver-operating characteristic curves for nonsurvival in dogs with AD was 0.710 (P = 0.039) for the NLR and 0.773 (P = 0.008) for the WBC.

CONCLUSIONS

Evaluation of NLR at hospital admission may be a useful marker of disease severity and may have prognostic value in puppies with AD. Further investigations are required to understand the implications of these findings.

Multiple Organ Dysfunction Syndrome Caused by Sepsis: Risk Factor Analysis

Purpose

To analyze the risk factors of multiple organ dysfunction syndromes (MODS) caused by sepsis.

Patients and Methods

A total of 180 patients with sepsis admitted to The First Affiliated Hospital of Harbin Medical University (No. 23, Post Street, Nangang District, Harbin 150001, Heilongjiang province, China) from July 2018 to June 2019 were selected and divided into a non-MODS group and a MODS group, with 90 cases in each group. Clinical data of the patients were retrospectively analyzed, and univariable and multivariable analyses were performed.

Results

The univariable analysis showed that there were no significant differences in terms of age, body temperature, heart rate, respiration, mean arterial pressure, RBC specific volume, blood sodium, serum kalium, and infection site (P > 0.05). Whereas significant differences were found between the groups in terms of gender, arterial blood pH, WBC count, Apache II score, blood glucose, creatinine, chronic medical history, surgery, and ventilator usage (P < 0.05). The growth of bacterial culture, the increase of creatinine level, chronic diseases and Apache II score were discovered to have significant effects on the occurrence of MODS through the multivariable logistic regression analysis.

Conclusion

Bacterial culture, serum creatinine level, history of chronic disease and Apache II score may be risk factors of MODS in sepsis patients.

Clinical features, outcome, and illness severity scoring in 32 dogs with urosepsis (2017-2018)

OBJECTIVE

To describe the clinical features, outcome, and utility of illness severity scoring in dogs diagnosed with urosepsis.

DESIGN

Retrospective study (2017-2018).

SETTING

University teaching hospital.

ANIMALS

Thirty-two dogs diagnosed with urosepsis secondary to pyometra, prostatitis, or pyelonephritis.

INTERVENTIONS

 None.

MEASUREMENTS AND MAIN RESULTS

Urosepsis was identified in 32 dogs, consisting of 9 of 32 (28.1%) with pyometra, 7 of 32 (21.8%) with prostatitis, and 16 of 32 (50%) with pyelonephritis. In total, 28 (87.5%) dogs survived to discharge, with the following group-specific survival rates: pyometra, 9 of 9 (100%); prostatitis, 5 of 7 (71.4%); and pyelonephritis, 14 of 16 (87.5%). Positive bacterial cultures were obtained in 27 of 32 (84.1%) dogs. The most commonly implicated pathogens were Escherichia coli (14/37 [37.8%]), Klebsiella pneumoniae (8/37 [21.6%]), and Staphylococcus pseudintermedius (6/37 [16.2%]). Multiple organ dysfunction syndrome (MODS) was identified in 21 of 32 dogs (65.6%). Although the presence of MODS was not different between survivors and nonsurvivors (P = 0.6), nonsurvivors had more dysfunctional organs (P = 0.04). Nonsurvivors also had higher Acute Patient Physiology and Laboratory Evaluation (APPLE_FAST ) scores compared to survivors (P = 0.01).

CONCLUSIONS

Survival of dogs with urosepsis was good and may be higher than for other sources of sepsis. Compared to survivors, nonsurvivors had more dysfunctional organs and higher illness severity scores, which may be helpful in the assessment and management of dogs with urosepsis.

Comparison of Protein Carbonyl (PCO), Paraoxonase-1 (PON1) and C-Reactive Protein (CRP) as Diagnostic and Prognostic Markers of Septic Inflammation in Dogs

Reliable diagnostic and prognostic markers of sepsis are lacking, but essential in veterinary medicine. We aimed to assess the accuracy of C-Reactive Protein (CRP), protein carbonyls (PCO) and paraoxonase-1 (PON1) in differentiating dogs with sepsis from those with sterile inflammation and healthy ones, and predict the outcome in septic dogs. These analytes were retrospectively evaluated at admission in 92 dogs classified into healthy, septic and polytraumatized. Groups were compared using the Kruskal–Wallis test, followed by a Mann–Whitney U test to assess differences between survivors and non-survivors. Correlation between analytes was assessed using the Spearman’s test, and their discriminating power was assessed through a Receiver Operating Characteristic (ROC) curve. PON1 and CRP were, respectively, significantly lower and higher in dogs with sepsis compared with polytraumatized and clinically healthy dogs (p < 0.001 for both the analytes), and also in dogs with trauma compared with healthy dogs (p = 0.011 and p = 0.017, respectively). PCO were significantly increased in septic (p < 0.001) and polytraumatized (p < 0.005) as compared with healthy dogs. PON1 and CRP were, respectively, significantly lower and higher in dogs that died compared with survivors (p < 0.001 for both analytes). Ultimately, evaluation of CRP and PON1 at admission seems a reliable support to diagnose sepsis and predict outcomes.

Evaluation and comparison of serum procalcitonin and heparin-binding protein levels as biomarkers of bacterial infection in cats

OBJECTIVES

As bacterial infection can lead to sepsis and high mortality, early and easy diagnosis of sepsis can improve survival. In cats, the diagnosis of systemic bacterial infection is quite challenging, and, usually, non-specific markers for inflammation are employed. In humans, procalcitonin, heparin-binding protein and absolute neutrophil count are biomarkers that are studied in bacterial infections and sepsis owing to their high sensitivity and specificity.

METHODS

A total of 56 cats were categorised into 16 healthy cats and 40 bacterially infected cats, diagnosed by various examinations. In all cats, serum procalcitonin and heparin-binding protein levels were measured using ELISA and an absolute neutrophil count was performed.

RESULTS

The median values of procalcitonin levels and absolute neutrophil count were significantly higher in the infection group than in the normal group, but heparin-binding protein levels were not. A procalcitonin level >366 pg/ml was a better biomarker of bacterial infection than heparin-binding protein and absolute neutrophil count (sensitivity: 67.5%; specificity: 93.8%). Procalcitonin was not correlated with heparin-binding protein (r = 0.213, P = 0.115) and absolute neutrophil count (r = 0.393, P = 0.003).

CONCLUSIONS AND RELEVANCE

High procalcitonin levels in cats were associated with bacterial infection. Hence, procalcitonin could be a valuable marker for diagnosing bacterial infections in cats.

Hypophosphatemia in Dogs With Presumptive Sepsis: A Retrospective Study (2008-2018)

Background: In humans with sepsis, hypophosphatemia is a marker of illness severity and a negative prognostic indicator. Hypophosphatemia has not been previously investigated in dogs with sepsis, however. This study aimed to estimate the prevalence of hypophosphatemia in dogs, the prevalence of presumptive sepsis in dogs with hypophosphatemia, the prevalence of hypophosphatemia in dogs with presumptive sepsis and the association between outcome and hypophosphatemia in dogs with presumptive sepsis. Methods: Electronic medical records of the Cornell University Hospital for Animals from 2008-2018 were queried to identify all dogs with hypophosphatemia and all dogs with presumptive sepsis. Hypophosphatemia was defined as a serum phosphate concentration <2.7 mg/dL. Sepsis was presumed where ≥2 of 4 systemic inflammatory response syndrome (SIRS) criteria were satisfied associated with a documented or highly suspected infection. Variables were assessed for normality using the D'Agostino-Pearson test. Continuous variables were compared between groups using the Mann-Whitney U test. Differences in frequency between categorical variables were analyzed using contingency tables, calculation of Fisher's exact test or Chi² and estimation of odds ratios. Results: In the study period, 47,992 phosphate concentration measurements from 23,752 unique dogs were identified. After eliminating repeat analyses, the period prevalence of hypophosphatemia on a per dog basis over the 11-year study period was 10.6% (2,515/23,752). The prevalence of presumptive sepsis within dogs with hypophosphatemia was 10.7% (268/2,515). During the 11-year study period, 4,406 dogs with an infection were identified, of which 1,233 were diagnosed with presumptive sepsis and had a contemporaneous phosphate concentration. Hypophosphatemia was more prevalent in dogs with presumptive sepsis than in dogs without 21.7 vs. 10.2%; OR 2.44 [95% CI 2.12-2.81]; P < 0.0001. The mortality rate was greater in dogs with hypophosphatemia and presumptive sepsis than in dogs with hypophosphatemia without presumptive sepsis (15.3 vs. 3.1%; OR 5.70 [95% CI 3.76-8.52]; P < 0.0001), however hypophosphatemia was not associated with outcome in dogs with presumptive sepsis OR 0.87 [95% CI 0.60-1.26]; P = 0.518. Conclusions: In dogs with hypophosphatemia, a presumed diagnosis of sepsis was associated with increased mortality compared to other associated disease processes. In dogs with presumptive sepsis, hypophosphatemia was not associated with outcome.

Circulating Methemoblogin Fraction in Dogs With Sepsis

Large amount of nitric oxide (NO) can be released in patients with sepsis. Methemoglobin is formed from the interaction between NO and hemoglobin. Mild methemoglobinemia reflecting NO overproduction has been reported in septic people, and occasionally associated to septic shock and organ dysfunction. The aim of this retrospective study was to evaluate circulating methemoglobin fraction in dogs with sepsis and to assess its prognostic value. Methemoglobin reference interval (RI) was calculated in 41 healthy dogs and was set at 0–2.2%. A total of 131 dogs with sepsis were included in the study; 24/131 had a circulating methemoglobin ≥2.2%. The median methemoglobin fraction was significantly higher in dogs with sepsis compared to healthy ones (1.7%, 0.4–3.5% vs. 1.0, 0.3–2.2%, P = 0.0005). No significant difference was observed between dogs with uncomplicated sepsis (n = 98) vs. dogs with septic shock (n = 33) (1.8%, 0.4–2.8% vs. 1.5%, 0.4–3.5%, P = 0.74), between dogs with and without multi-organ dysfunction (n = 38 and n = 93, respectively) (1.7%, 0.4–3.5% vs. 1.7%, 0.5–2.8%, P = 0.27), and between survivors (n = 77) vs. non survivors (n = 54) (1.5%, 0.4–2.8% vs. 1.8%, 0.4–3.5%, P = 0.05). Dogs with methemoglobin fraction above or equal to the upper limit of the RI had a significantly higher frequency of death compared to dogs with methemoglobin levels <2.2% (60.0% vs. 36.8%, P = 0.04). In conclusion, mild methemoglobinemia is detected in dogs with sepsis, and methemoglobin values above the RI might be associated with a worse outcome.

Serum procalcitonin concentrations in dogs with induced endotoxemia

Background

Procalcitonin (PCT) is an important biomarker for sepsis in human medicine, but there is little information regarding PCT as a biomarker for sepsis in dogs. There are no controlled studies evaluating serial concentrations of PCT in dogs.

Hypothesis/Objective

That PCT would be rapidly detectable in serum after injection of LPS and would remain increased for at least 24 hours. Objective was to evaluate serial serum PCT concentrations in dogs after a single IV injection of LPS compared to placebo.

Animals

Six healthy mixed breed dogs.

Methods

A nonrandomized, placebo‐controlled, crossover study was performed. Dogs were initially injected with placebo (0.9% NaCl; 1 mL, IV) and then experimental endotoxemia was induced by injecting lipopolysaccharide (LPS; 2 μg/kg, IV, once) after a 5‐day washout period. Serial blood samples were collected for measurement of serum PCT after each injection. Difference in median PCT concentration between serial time points was assessed using a mixed effects model.

Results

After LPS administration, blood pressure decreased and body temperature increased along with the development of lethargy, vomiting, and diarrhea. Procalcitonin was significantly increased compared to baseline by 2 hours after injection of LPS (median = 67.9 versus 172.8, range = 46.0‐74.1 versus 99.5‐295.9, P = .0002) and remained significantly increased for 12 hours (median = 205.9, range = 119.9‐297.4) with return to baseline by 48 hours. Procalcitonin was significantly higher than placebo 2, 4, 6, 8, 10, 12, and 24 hours after injection. There were no significant differences in PCT between time 0 and any of the subsequent time points in the saline group.

Conclusions and Clinical Importance

Procalcitonin expression is likely to be a clinically useful biomarker for sepsis in dogs and might have an additional role in prognostication and therapeutic decision‐making.

Biomarker Guided Diagnosis of Septic Peritonitis in Dogs

Septic peritonitis (SP) is common in dogs and is associated with high mortality. Early recognition is essential to maximizing survival and may be aided by biomarker measurement. The present study aimed to evaluate the ability of biomarkers to discriminate septic peritonitis from non-septic ascites (NSA). Eighteen dogs with SP and 19 age-matched controls with NSA were enrolled. Contemporaneous blood and peritoneal effusion samples were obtained. Concentrations of cell-free DNA (cfDNA), cytokines, glucose, lactate, N-terminal pro-C-type natriuretic peptide (NT-proCNP), nucleosomes, and procalcitonin (PCT) were measured using commercial reagents and assays. Paired biomarker concentrations were compared with the Wilcoxon matched-pairs signed rank test, and biomarker concentrations between groups were compared with the Mann-Whitney U-test. P-values were adjusted for multiple comparisons using the Bonferroni correction. Receiver operating characteristic curves were generated to assess the ability of the above biomarkers to discriminate SP from NSA. Dogs with SP had significantly greater blood CCL2 concentrations than dogs with NSA (P = 0.032). Dogs with SP had significantly greater effusion CCL2, IL-6, IL-10, and lactate concentrations than dogs with NSA (P ≤ 0.0121). Blood-effusion concentration gradients of CCL2, glucose, IL-6, IL-10, and lactate were significantly different in dogs with SP compared to dogs with NSA (P ≤ 0.0165). Effusion lactate concentration had the highest AUROC value (0.866, 95% CI 0.751–0.980, P = 0.0001), although other biomarkers performed similarly. An effusion lactate concentration of 4.2 mmol/L was 72.2% (95% CI 46.5–90.3%) sensitive and 84.2% (95% CI 60.4–96.6%) specific for the diagnosis of SP.

Agreement between Parallel Canine Blood and Urine Cultures: Is Urine Culture the Poor Man's Blood Culture?

Bloodstream infections are a significant cause of morbidity and mortality in critically ill dogs, but due to cost and difficulties in sample acquisition, blood cultures are infrequently obtained. In ill dogs, urine cultures may be recommended as surrogates for blood cultures. In order to determine the outcome agreement between parallel urine and blood cultures, we retrospectively analyzed parallel blood and urine specimens submitted for culture from dogs at the NC State Veterinary Hospital between 2011 and 2016. Positive cultures were reported from 15% of the submitted blood specimens and 23% of the submitted urine specimens. A total of 295 urine and blood samples were submitted in parallel, with positive growth demonstrated in 14 concordant and five discordant pairs. A kappa statistic comparing blood and urine culture outcomes was 0.266 (fair) when all parallel growth was included, including concordant and discordant results, and 0.170 (poor) when restricted to parallel concordant growth. The sensitivity of urine to reflect concordant bloodstream bacterial organisms was 30%, with a specificity of 87%. The positive and negative predictive values were 30% and 88%, respectively. Of dogs with both specimens positive on bacterial culture, 7 of 7 (100%) with suspected urogenital infection sources were concordant. All dogs with discordant bloodstream and urinary infections were immunosuppressed. Urinary coagulase-positive Staphylococcus isolates were most likely to be concordant with bloodstream infections. In conclusion, we found that urine culture is neither a substitute nor a screen for blood culture. Blood cultures should be performed in any potentially septic animal, especially those that are considered immunosuppressed.

Cell-Free DNA, High-Mobility Group Box-1, and Procalcitonin Concentrations in Dogs With Gastric Dilatation-Volvulus Syndrome

Canine gastric dilatation–volvulus (GDV) is a life-threatening disease characterized by extensive tissue ischemia, tissue hypoperfusion, and systemic inflammation. Biomarkers that better reflect the severity of gastric necrosis and systemic inflammation would aid clinicians in the management of these patients. This study aimed to investigate the prognostic significance of cell-free DNA (cfDNA), high-mobility group box-1 (HMGB1), and procalcitonin (PCT) in dogs with GDV. Concentrations of cfDNA, HMGB1, and PCT were measured in citrated plasma samples collected from 29 dogs with GDV at hospital admission. Additional data collected included baseline lactate concentrations, APPLE_fast score, evidence of gastric necrosis, occurrence of postoperative complications, and outcome. Twenty-four healthy dogs were sampled as controls. Continuous variables between groups were compared with the Mann–Whitney U and correlations between continuous variables were assessed by calculation of Spearman’s correlation coefficient. Alpha was set at 0.05. Dogs with GDV had significantly greater concentrations of cfDNA, HMGB1, and PCT compared to controls (P = 0.0009, P = 0.004, and P = 0.009, respectively). PCT concentrations were significantly higher in non-survivors compared to survivors (P = 0.008). Dogs with gastric necrosis had significantly greater lactate concentrations compared to dogs without gastric necrosis (P = 0.0005). The APPLE_fast score was not prognostic. Lactate and PCT concentrations were moderately, positively correlated (r_s 0.51, P = 0.0005). Concentrations of the inflammatory biomarkers cfDNA, HMGB1, and PCT are increased in canine GDV. Only lactate and PCT concentrations were prognostic in this population of GDV dogs and were predictive of the presence of gastric necrosis and of non-survival to hospital discharge, respectively.